Optics letters最新文献

Zou-Wang-Mandel (ZWM) quantum-induced coherence has been demonstrated for high-sensitive detection and sensing applications such as high signal-to-noise ratio ranging and imaging in complex environments. The path overlapping of the idler prohibits the determination of the exact path from which the signal originates. However, the interference region of quantum-induced coherence is limited to coherence length of parametric down-conversion (PDC) photons generated by nonlinear processes, which has remained an urgent issue to address. Here, we propose a method to increase the interference region of quantum-induced coherence imaging systems, from micrometers to centimeters at least by seed injection (SI) of the same frequency as the idler, and resulting in brighter fringes. Compared to typical ZWM quantum-induced coherence imaging, our system not only retains the advantages of noise resistance and no coincidence requirement but also exhibits possibilities of high-coherence, long-distance, and high-visibility imaging.

We demonstrate a patterned vertically aligned (PVA) liquid crystal display (LCD) driven by a reverse-voltage scheme that achieves submillisecond response times (0.52 ms). Both simulations and experiments confirm that the device consistently operates within the submillisecond regime, thereby validating the feasibility of the proposed approach. This method optimizes the LC molecular deformation dynamics and reverse-bias driving strategy, effectively overcoming the intrinsic response-time limitations of conventional in-plane switching (IPS) and fringe-field switching (FFS) LCDs, consequently meeting the core requirements of next-generation augmented reality (AR) and virtual reality (VR) display technologies for improved dynamic display performance.

Silica nanocomposites-based processes provided a new route for low-temperature fabrication of fused silica components. However, low accuracy and poor surface quality prohibit their applications for generating fused silica optics. Herein, we report what we believe to be a novel process for ultra-precision fabrication of complex-shaped fused silica micro-optics by diamond turning of partially debound silica nanocomposites, where the partially debound nanocomposites were designed to suppress undesired deformations in the high-temperature processing. By practically characterizing the generated fused silica components, the optimum partial debinding temperature was selected as 275°C. As a demonstration, an achromatic refractive-diffractive hybrid lens with long focal depth was fabricated to have a surface roughness of Sa = 6.01 nm and a PV error of around 0.46 μm.

Photonic switching technologies have been proffered as competitive replacements for electronic switches, due to high power efficiency, high bandwidth density, and low cost. Here, a high-performance 1 × 8 thermo-optic switch based on artificial gauge field engineered waveguide superlattices is proposed. This switch exhibits an average insertion loss of 1.96 dB and keeps crosstalk below -20 dB over a 60 nm bandwidth. By leveraging topology optimization, this thermo-optic phase shifter eliminates the need for intricate air-trench or undercut processes while delivering exceptional metrics: low power consumption (2.52 mW/π), low loss (0.4 dB), sub-1V driving voltage for 2π tuning, wideband operation (60 nm), and a compact footprint (245 μm × 15 μm).

Reliable bonding of non-optical-contact ceramic and glass is crucial for the fabrication of microdevices but remains challenging due to their distinct thermophysical properties and non-uniform interface. In this study, femtosecond laser welding of alumina ceramics with a surface roughness of 4.82 μm and fused silica under non-optical-contact conditions were achieved with a weld strength of 13.75 MPa. The laser parameters (200 fs, 1030 nm, 1000 kHz, 23.8 μJ, 40 mm/s scanning speed) were used for welding. Under the rapid thermal accumulation induced by the high-repetition rate femtosecond laser, the high-speed imaging system captured the coexistence of internal and interfacial plasma, occurring during the welding process. The internal plasma generated by nonlinear absorption remained localized at an almost constant height above the interface during the steady melting stage, while interfacial plasma showed continuous upward growth in sequence and finally produced a discrete modified region both within fused silica and at the interface, indicating it as a highly stable welding process. Detailed analysis revealed that the dual-plasma interaction promotes localized melting, interfacial diffusion, and mechanical interlocking between fused silica and ceramics. This work elucidates the feasibility and dynamic mechanism of femtosecond laser welding of alumina ceramics and fused silica under non-optical-contact conditions, providing experimental and theoretical guidance for precision joining of dissimilar materials.

In recent years, optical skyrmions have garnered significant attention due to their unique properties and potential applications. These skyrmions, which include optical field skyrmions, optical spin skyrmions, and optical Stokes skyrmions, exhibit deep-subwavelength and topologically stable characteristics that make them highly suitable for various technological applications such as microscopy, metrology, sensing, and memory. In this context, we present a theoretical proposal for the generation of optical spin skyrmions in a tightly focused partially coherent beam. Our study delves into the behavior of these skyrmions as a function of the coherence length of the beam. Optical spin skyrmions fabricated by spin-orbit coupling of a partially coherent optical vortex are not limited by the topological charge m of the optical vortex. This investigation is particularly novel as we believe it marks the first instance where skyrmions have been identified in a partially coherent beam.

The integration of high-speed optical communication and distributed sensing could bring intelligent functionalities to ubiquitous optical fiber networks, such as seismic detection, while in the face of a major challenge of constructing a long-haul thousand-kilometer fiber link. This work proposes the first, to our knowledge, interconnected counter-propagating recirculating loop (ICP-RL) with high-loss loop back (HLLB) path as a compact in-lab platform for ultra-long-haul integrated sensing and communication (ISAC), and experimentally demonstrates a simultaneous 32-GBaud PMD-QPSK signal transmission and distributed acoustic sensing (DAS) system application with a spatial resolution of 3.3 km over 3651-km SSMF. The recirculating loop is controlled by acoustic-optical modulators, which also provide an essential frequency shift for the Rayleigh backward scattering sensing signal distinction. The proposed ICP-RL makes possible a low-cost in-lab validation platform for long-haul ISAC systems during the research and development (R&D) phase.

Overcoming diffraction spreading is a crucial challenge in wave physics. We report a mechanism for suppressing diffraction of skyrmionic polarization textures by leveraging anisotropic absorption in inhomogeneous media. We show that dichroic media with a longitudinally varying degree of dichroism can compensate the diffraction spreading of the skyrmion tube, enabling the formation of non-diffracting Stokes skyrmions. In contrast to trapped waves in gradient-index media, we present a non-diffraction mechanism in media with uniform refractive index in the transversal direction, thus the finite-size vortex beams themselves experience diffraction, but their combined polarization texture remains confined within a non-spreading tube. We also show the robustness of the non-diffraction mechanism under changes in the input beam size and under beam shifts along longitudinal and transversal directions.

We report a tellurite anti-resonant hollow-core fiber (AR-HCF) with a nested capillary structure. To the best of our knowledge, this fiber, comprising five sets of nested double-layer capillaries around the air core, is the first nested AR-HCF fabricated using infrared glass. Benefiting from the enhanced light confinement capability of the nested capillary design, the fabricated fiber achieves a low transmission loss of 0.15 ± 0.04 dB/m at a single wavelength of 4.65 μm measured by cutting from 3 m to 1 m. A 0.8-m-long nested tellurite AR-HCF delivers near-diffraction-limited laser output, with a beam quality (M²) of 1.07. Numerical simulations confirm that the nested structure reduces confinement loss by approximately two orders of magnitude compared to the single-layer capillary configuration. With further optimization of the fabrication process, the nested tellurite AR-HCF is expected to achieve lower losses, thereby demonstrating substantial potential for applications in mid-infrared (3-10 μm) laser transmission systems.

We present a hybrid multiplexing method for holographic optical storage that combines complex-amplitude encoding with polarization- and angle-based multiplexing to enhance storage density and capacity significantly beyond conventional approaches. By leveraging polarization holography, complex-amplitude data can be selectively recorded into orthogonal polarization channels. Furthermore, angular multiplexing is also applied to co-record multiple holograms at the same spatial location. During the reading process, each hologram can be selectively reconstructed under its specific Bragg and polarization conditions. Remarkably, despite exploiting these degrees, the reconstruction fidelity remains exceptionally high, with negligible degradation or crosstalk. This demonstrates a scalable route to high‑capacity, high‑fidelity holographic memories for next‑generation data‑intensive applications.